Once they create your CAIPS file, your application started being processed. "In process" is basically not user entry. It's computer entry. When CAIPS file created, computer system automatically updates your status as "In process". About Medical results, some Visa mission updates, some not.
Until they complete assessing your file ( Including review by VO, Background / Security/Medical Checks done), It will Show "In process".
During "In process" stage, they complete your Record Check (R/C), Sponsor's Foss Check, See NCB Entry if any, Paper Screening, Background, Security and Medical results. Most important part is "Paper Screening" also knows as PSDEC. This part is important. Most of the applications initial decision is taken at this stage ( Whether missing documents, required additional documents, interview recommendation, and redirecting your file to the assigned VO for reviews). If interview is recommended, it is forwarded to the assigned VO for your case for confirmation. Once VO confirms, Interview decision letter is sent to the applicant. This is how it works. If no interview is required, interview waive decision ( Selection Decision is entered 1 or 4) taken and the process gets quick completion.
So, it's long process. In some cases, applications are reviewed 2 or 3 times. This happens when VO needs more time to come for decision. Or when additional supporting documents are received. Every time, additional supporting documents sent to the Visa Office, those need to be reviewed by VO. So, try to send all documents at one time.
In skill class category, process part is almost same except Visa office will frame it in longer processing time category.
You could look at cic website for application processing time for your country's visa mission.
Hope it helps. Cheers.
